Process for the production of impregnated paper and the like



Feb. 28, 1933. HlLL 1,899,688

PROCESS FOR THE PRODUCTION OF IMPREGNATED PAPER AND THE LIKE Filed March 51, 1931 ATTORNEYS Y Patented Feb. 28, 1933 UNITED STATES PATENT" OFFICE HARRY HILL, 0]? BELVEDERE, ENGLAND, ASSIGNOR TO CALLENDERS CABLE AND CON- STRUCTION COMPANY LIMITED, 0]? LONDON, ENGLAND, A BRITISH COMPANY PROCESS FOR THE PRODUCTION OF IMPREGNATED PAPER AND THE LIKE Application filed March 31, 1931, Serial No. 526,757, and in Great Britain April 10, 1930. V

The invention deals with the impregnation of paper or other material in the form of long pieces with liquid or semi-liquid material. Processes at present in use for this purpose are oftwo types. In one the material, which is in the form of a roll, is unrolled and drawn through a tank of the impregnating liquid and therefore materials which are more suitable for many purposes cannot be employed with certainty of obtaining complete and uniform impregnation. In the second case it is difficult to obtain uniform impregnation of difierent parts of the roll as the impregnating 'material will not readily penetrate to the interior.

The present invention provides an improve ment on the second method of procedure which facilitates the impregnation of the material without seriously adversely affecting its structure and tensile strengh and permits of the use of larger rolls than could otherwise be considered practicable. In accordance with the invention, the material in the roll un dergoes an embossing process of sucha nature;

that it produces a number of comparatively small and preferably isolated raised areas but leaves the greater part of the material lying in the original plane thereof and substantially unaffected, after which it is rolled in flat spiral in such a way that the raised parts form spacers to keep the layers of the roll apart, thus producing a roll ofsufiiciently open form to permit the impregnating material to flow in readily from the ends. A roll thus prepared is placed in the impregnating chamber and subjected to an appropriate treatment 7 which may include the use of heat, vacuum or pressure or a combination of any two or more of these.

An example of paper sultably embossed the piece of embossed paper taken on the line XX in Figure 1 buton a scale which is twice that to which Figure 1 is drawn.

Figure 3 is a perspective View of a roll of paper embossed as shown in Figures 1 and 2, the roll itself being shown on a reduced scale whilst, for the sake of clearness, the projections and the spacing thereof are shown on a scale approximately four times as great as that employed for the roll.

This embossed paper is produced by pressing small rounded tools into one of the surfaces of plain paper so as to produce on the side B more or less conical depressions 1 and at corresponding places on the side A more or less conical projections 2. These projections 2 are distributed more or less uniformly at short intervals all over the surface of the paper; Figure l shows the appearance of the indented side of such embossed paper and, with Figure 2, gives an idea of the size of the projections and spacingthereof preferred for paper the ,thickness of which is about 5 to 6 mils. It should be understood that the desired spacing between adjacent convolutions in a roll of paper which it is desired .toimpregnate, may be produced other than by embossing the paperin the precise manner illustrated inthe drawing. Variously shaped projections may be produced on one or both sides of the paper and the size and spacing of the projections may be varied to suit different conditions.

After having been subjected to the emboss- -ing process the paper is rewound, preferably to form fiat rolls, such as that illustrated in Figure 3, in. which the adjacent convolutions of each roll are spaced apart by the projections 2 thus permitting the passage of impregnating material between convolutions of paper and so enabling the whole ofthe paper in the roll to be substantially more evenly and thoroughly impregnated than would be the case were no spacing between adjacent convolutions provided.

Owing to the facility of impregnation which is obtained by the im roved process, it 5 is possible to employ desirable impregnating media which are inapplicable under other conditions owin to their high viscosity or other characteristics which hinder them from penetrating to the interior of the material. For example, by means of this improved process, it is possible to produce a paper which may be thoroughly impregnated whilst in roll form with undiluted tar. and which may be used to protect lead sheaths and armouring of cables ,from corrosive influences. Furthermore, paper so impregnated has a quantity of undiluted tar on its surface which, in addition to providing a medium. for immediate adhesion to the armouring compounds applied at the armouring machine, acts as a lubricant and ensures that as the paper is applied to. the cable it readily pulls down and assumes a very close fit and generally assures a good and improved adhesive covering without voids.

Although the examples given above have dealt with the impregnation of paper strip, the process is equally applicable to other but analogous materials such as cambric.

What I claim as my invention and desire to secure by Letters Patent is 1. An improved process for the impregnation with liquid or semi-liquid material of paper or other material in the form of long pieces, which process comprises embossing the material at a plurality of comparatively small areas but leaving the greater part of the material lying in the original plane thereof and substantially unaffected, rolling it up in such a way that the raised parts form spacers to keep the layers of the roll apart, thus producing a roll dfl sufliciently open form, and finally impregnating the roll.

2. An improved process for the impregnation with liquid or semi-liquid material of paper or other material in the form of long pieces, which process comprises providing the material with series of substantially uniformly spaced and approximately conical projections by an embossing process which leaves the greater part of the material lying in the original plane thereof and substantially unaffected, rolling up the material in such a way that the projections form spacers to keep the layers of the roll apart, thus producing a roll of sufficiently open form, and finally impregnating the rol In testimony whereof I aflix my signature.

HARRY HILL.- 

